Linear motion devices are actuators which convert non-linear motion (e.g., rotary motion) to linear motion. Various types of linear motion devices are known and include, for example, traveling nut actuators such as lead screw assemblies and ball screw assemblies. Various types of lead screw assemblies and ball screw assemblies are known in the art. These devices convert rotary motion to linear motion, or vice versa, while supporting axial loads along the screw shaft. A limitation to convention systems is the reduction of performance and useful life when a radial load (i.e., a load applied perpendicular to the screw shaft) and/or a moment load (i.e., a bending load) is applied to the assembly. To compensate for such non-axial loads the linear guide system must be made of stronger, and therefore heavier and more costly components. Typical guide systems under present technology use round or square linear shafts and bearings. Such guidance systems are usually expensive to both make and maintain. They require extensive installation alignment features and periodic maintenance to ensure proper functioning. What is needed is a simpler assembly which reduces the cost, complexity and size of the system.
Moreover, lubrication is required whenever there is metal to metal contact. Such lubrication is typically done by application of a grease or oil. However, this is unacceptable where the apparatus cannot be serviced or where application of a lubricant is undesirable to the environment as, for example, in medical, food processing, semiconductor fabrication, etc.